Importance of positive feedback

Alexander Hoffmann/Marcelo Behar

A computer model of the B cell’s key molecular circuit shows the importance of the strength of positive feedback in producing a black-or-white, rather than a gray, threshold response. This figure shows no feedback strength, a little feedback strength and a lot of feedback strength (0-2, where 2 is high feedback and 0 is low feedback). The colors and height indicate the strength of the response. A red response is high; a blue response is low.

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